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Xiaoqing Zhang1 Jiayuan Shi1 Yong Xiang1

1, University of Electronic Science and Technology of China, Chengdu, , China

Nano layered double hydroxides Ni-Al-Li-LDHs was firstly introduced into Lithium-ion battery to modify LiFePO4 (LFP) cathode. The 3D "Silk flower" like Ni-Al-Li-LDHs were in-situ grown on the surface of LFP by hydrothermal method with specific mole ratios of LFP/LDHs. A series of structural characterization have been carried out on these composites. The XRD, SEM, FT-IR and TEM test results reveal that Ni-Al-Li-LDHs was truly grown on the surface of LFP and formed a core-shell like structure. Then these LFP/LDHs composite were taken as cathode materials in lithium battery. Their electrochemical performance were detected by electrochemical impedance spectroscopy (EIS), cyclic voltammetry(CV), galvanostatic charge-dischage cycling. Both electrochemical activity and stability of LFP have obtained significant progress by Ni-Al-Li-LDHs optimizing. The highest specific capacity was obtained by LDHs/LFP (mole ratio 1:4) as 180 mAhg-1, which is much higher than that of pure LFP cathode (120 mAhg-1) . Moreover, the stability of these composites cathode were also outstanding by 200 cycling evaluation. The excellent performances of LFP/LDHs cathode in lithium ion battery were due to the enhancement of lithium ion mobility by Ni-Al-Li-LDHs. Which based on the unique layered by layered structure and ion exchangeable ability of Ni-Al-Li-LDHs. Besides, LDHs also enlarge the specific surface area of LFP by N2 adsorption-desorption experiment. Which have provided more active site for electrochemical reaction. Modifying LFP by Ni-Al-Li-LDHs was a novelty attempt and achieved some positive results.

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